Chain guide for use in a heat treating oven or the like and method of manufacture

ABSTRACT

A chain guide for use in a high temperature environment, such as a heat treating oven, and method of manufacture, the chain guide comprising an elongated planar base plate having two parallel longitudinal edges and made of a relatively nonporous homogeneous material, and longitudinal guide walls made of a relatively nonporous homogeneous material which are fixed as by welding to the longitudinal edges of the base plate. The guide walls have integral flanges, overlying the base plate, provided with longitudinal edges which are separated a predetermined distance to provide a guide slot through which extends a driving member attached to the driving chain otherwise enclosed by the guide walls and base plate. The guide wall flanges are formed prior to assembly of the guide walls to the base plate as by forging, rolling, swaging, or other comparable forming methods well known to the art.

United States Patent [191 Wright [451 Nov. 25, 1975 4] CIIAIN GUIDE FOR USE IN A IIEAT TREATING OVEN OR THE LIKE AND METHOD OF MANUFACTURE [76] Inventor: Joseph D. Wright, 209 W. Ohio St.,

Kendallville, Ind. 46755 [22] Filed: Dec. 20, 1974 [21] Appl. No.: 535,038

[52] US. Cl. 74/240 [51] Int. Cl. F16 7/18 [58] Field of Search 74/240, 611

[56] References Cited UNITED STATES PATENTS 975,721 11/1910 Russell 74/240 3,343,880 9/1967 Hauschopp.... 74/61] x 3,515,013 6/1970 Wykes 74/611 Primary ExaminerLeonard H. Gerin [5 7] ABSTRACT A chain guide for use in a high temperature environment, such as a heat treating oven, and method of manufacture, the chain guide comprising an elongated planar base plate having two parallel longitudinal edges and made of a relatively nonporous homogeneous material, and longitudinal guide walls made of a relatively nonporous homogeneous material which are fixed as by welding to the longitudinal edges of the base plate. The guide walls have integral flanges, overlying the base plate, provided with longitudinal edges which are separated a predetermined distance to pro vide a guide slot through which extends a driving member attached to the driving chain otherwise enclosed by the guide walls and base plate. The guide wall flanges are formed prior to assembly of the guide walls to the base plate as by forging, rolling, swaging, or other comparable forming methods well known to the art.

5 Claims, 4 Drawing Figures US. Patent Nov. 25, 1975 CHAIN GUIDE FOR USE IN A HEAT TREATING OVEN OR THE LIKE AND METHOD OF MANUFACTURE BACKGROUND or THE INVENTION 1. Field of the Invention This invention pertains to an improved chain guide for use in a high temperature environment such as a heat treating oven, and a method of manufacture of the chain guide.

2. Description of the PriorArt For many years work pieces have been moved in heat treating furnaces by a chain drive which, in many cases, has been mounted in the furnace floor and which carries a driving member, such as a pusher rod, which extends above the level of the furnace floor and contacts the work piece container, such as a basket, for moving the container internally of the furnace. Furnace floors are frequently of a refractory material which is brittle in nature, and which would tend to fragment upon constant wear due to contact with a moving chain. This would not only require replacement of the refractory material but would also cause accelerated chain wear due to the refractory particles becoming lodged between the moving parts of the chain. Hence, a chain guide would ordinarily be placed in the oven floor substantially enclosing the chain except for a longitudinal slot through which the driving member extended. conventionally, the chain guide has been a cast unitary tubular member of oblong cross section with a narrow longitudinal slot formed in the upper surface thereof through which the driving member extended. These chain guides required relatively frequent replacement due to distortion and/or breakage of the guide. The teaching of this invention recognizes the cause of such distortion and breakage and provides an improved structure made in an improved manner.

BRIEF SUMMARY OF THE INVENTION This invention recognizes that a major cause of the previous frequent distortion and breakage of the chain guides was due to the pores, voids, and lack of homoge neity in the cast material, such as cast iron. The distortion and breakage resulted from the very hostile environment of a furnace, the extreme temperature cycling in such a furnace, and the constant abrasion and wear of the chain on the chain guide as well as the shock imparted by virtue of the driving member driving the work piece container.

In the improved structure of this invention, a base plate of nonporous material with a longitudinal dimension corresponding to the longitudinal dimension of the furnace through which the work container is moved and having a lateral dimension corresponding to the chain width, is attached to two guide walls of nonporous homogeneous material having similar longitudinal dimensions and having a height corresponding to the chain height, with each guide wall having an integral flange overlying the base plate. The longitudinal edges of the flanges are separated a predetermined distance to form a guide slot through which the driving member, which is attached to the driving chain, extends. By making the flanges integral with their respective guide walls, assembly operations are simplified and minimized since welding of a flange to a guide wall is made pairs.

This invention further teaches the asembly of a chain A guide by fabrication techniques, as opposed to the conventional casting techniques, whereby a nonporous homogeneousmaterial such as stainless steel may be utilized as the chain guide material greatly'increasing chain guide life.

In the improved method of this invention, the chain guide is fabricated from three stainless steel pieces to form a semi-enclosed housing for the chain which is nonporous, homogeneous, and has a relatively long service life.

It is therefore an object of this invention to provide, in an oven environment for heat treating metal articles, a chain guide which houses and encloses a chain for supplying a driving force to a pusher member or the like to move a work piece container in the oven, which guide has a relatively long life and requires less frequent repair and replacement, decreasing down time of the oven and minimizing repair costs.

Another object of this invention is to provide such a chain guide made of an unporous material that has a longitudinal base plate with longitudinal guide walls attached, as by welding, to either side of the base plate, with each guide wall being formed to have a portion upstanding from the base plate and having an integral flange overlying the base plate, with the longitudinal edges of the flanges being laterally spaced a predetermined amount to provide a guide slot for the driving member.

It is a further object of this invention to provide'a method of manufacture for a chain guide which comprises the steps of forming a longitudinal base plate, forming a guide wall of unporous material with an integral flange, fixing, as by welding, a guide wall to each longitudinal edge of the base plate so that each flange overlies the base plate and the longitudinal edges of the flanges are spaced apart a predetermined distance from.

one another to form a guide slot.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a broken away view in perspective of a heat treating oven having a chain guide of this invention;

FIG. 2 is a side view of a chain guide of this invention;

FIG. 3 is a top plan view of the embodiment of FIG. 2; and

FIG. 4 is an end view.

DESCRIPTION OF A PREFERRED EMBODIMENT In FIG. 1 is shown an oven 20 having an oven floor 22 with an elongated trough 24 formed therein and an oven door 26 at one end in longitudinal alignment with trough 24. A work carrier 28, such as a basket, is shown positioned in oven 20 and normally contains articles for heat treatment in oven 20. The heating means for oven 20 is not shown but may be any of those well known to 3 the art.

In trough 24 is chain guide 30 which houses and encloses chain 32 which carries driving member 34 in fixed relation to a link thereof so that as the chain is moved, as by sprockets 35, driving member 34 is caused to move longitudinally along guide 30 and when in contact with basket 28 will move basket 28 towards door 26. In the embodiment shown in FIG. 1, the basket 28, at the beginning of the heat treating process, is placed in door 26 and then is pushed, with a rod or other member, to the desired position in furnace 20. After the heat treating operation has been completed, the chain motor is energized moving chain 32 and pusher member 34 towards door 26 positioning carrier 28 to be removed from the furnace 20.

Chain guide 30 is shown in detail in FlGS. 24. Referring to the figures, the chain guide will be described and subsequent thereto, a preferred method of manufacture will be described. Chain guide 30 comprises a base plate 36 which is made of a nonporous homogeneous material, such as stainless steel 38-19, and has a longitudinal dimension corresponding to the longitudinal dimension of the trough 24 in furnace 20. The longitudinal dimension of guide 30 is less than the longitudinal dimension of furnace by a suitable amount so that carrier 28 will not be completely ejected from furnace 20 by pusher member 34 but will be positioned relative door 26 so that it can be easily removed by the furnace operator. The width of base plate 36 corresponds to the width of chain 32 and is sufficiently wide so that the chain easily moves in the guide, to be later described.

Base plate 36 has an oblong slot 38 at one end thereof and has at the other end thereof an oblong notch 40. Plate 36 also has a plurality of longitudinal slots 42 each of which has radiused end portions, which slots 42 are for drive sprockets 35 (not shown in FIGS. 2, 3 and 4).

Base plate 36 has longitudinal edges 44, 46 to which cause chain wear. Walls 48, 50 are formed to have orthogonal flanges 52, 54, respectively, which overlie base plate 36 and have longitudinal edges 56, 58, respectively, which are spaced a predetermined distance apart and form a longitudinal slot 60 for guiding drive member 34 which is attached to a link of chain 32. By forming walls 48, 50 with flanges 52, 54, respectively, a welding operation is eliminated along with the attendant grinding and polishing of corner weld flashes. This minimizes assembly operation and assembly costs. Guide wall 50 is shorter than guide wall 48 by the length of notch 40. Mounting brackets 62, 64 are attached as by welding to guide walls 48, 50, respectively, in order to facilitate mounting of the guide in the furnace 20. Stops 66, 68 are attached as by welding to flanges 52, 54, respectively, and are used to index the carrier 28 on its insertion in furnace 20.

The method of fabricating guide 30 comprises the steps of forming base plate 36 to the desired longitudinal and lateral dimensions; forming guide walls 48, 50

and bending these walls along a longitudinal line, as by forging, rolling, swaging or other comparable metal forming operations, to form flanges 52, 54, respectively; and attaching guide walls 48, 50, to base plate 36, as by welding, along longitudinal edges 44, 46, respectively. This method of fabrication is to be contrasted with the conventional unitary casting process which has been practiced for many years. The method of this invention has a combination of steps which provide for the use of a nonporous, homogeneous material which has greatly increased life over the prior art chain guides.

This invention recognizes the cause for the relatively frequent failures of prior art cast iron devices and provides for a method of manufacture and an apparatus which overcomes the causes of these failures. Further, due to forming of the orthogonal flanges from the guide walls and the exterior welding of the guide walls to the base plate, the amount of weld material interiorly of the guide is minimized thereby making possible a substantially enclosed structure. Cleaning of weld material from a substantially enclosed structure is a difficult, often prohibitive, process.

While there have been described above the principles of this invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention.

What is claimed is:

l. The improvement in chain guide apparatus for enclosing a driving chain carrying a driving member in a high temperature environment comprising,

a relatively nonporous, homogeneous elongated base plate,

said base plate having a lateral dimension greater than the width of the driving chain,

a relatively nonporous, homogeneous first guide member having a longitudinal dimension corresponding to said base plate longitudinal dimension and being welded to one of said base plate longitudinal edges,

said first guide member having a first guide wall upstanding from said base plate a distance corresponding to the driving chain height,

a first guide flange being formed integrally with said first guide wall and having a longitudinal dimension corresponding to said first guide wall longitudinal dimension and being substantially orthogonal to said first guide wall to overlie said base plate,

a relatively nonporous, homogeneous second guide member having a longitudinal dimension corresponding to said base plate longitudinal dimension and being welded to the other of said base plate longitudinal edges,

said second guide member having a second guide wall upstanding from said base plate a distance corresponding to the driving chain height,

a second guide flange being formed integrally with said second guide wall and having a longitudinal dimension corresponding to said second guide wall longitudinal dimension and being substantially orthogonal to said second guide wall to overlie said base plate, thereby forming a chain enclosure,

the longitudinal edges of said first and second flanges being spaced apart a predetermined distance to form a longitudinal guide slot adapted to receive and guide said chain driving member.

2. An apparatus in accordance with claim 1 with said base plate and guide members being formed of stainless steel.

3. An apparatus in accordance with claim 1 with said first and second guide members overlapping the longitudinal edges of said base plate to provide a weld edge externally of the chain enclosure,

said flanges being welded along said external weld edge thereby minimizing weld material interiorly of l bending each of said guide members along a longitudinal line to form a longitudinal, integral right angle flange on each of said guide members,

welding one of said guide members to one of the longitudinal edges of said base plate and welding the other of said guide members to the other of the longitudinal edges of said base plate so that said guide members extend towards one another to form a chain enclosure and said flanges are spaced apart one from the other to define a longitudinal guide slot.

5. The method of claim 4 with the step of welding the guide members to the longitudinal edges comprising,

overlapping the guide members with the longitudinal edges of the base plate to form weld edges externally of the chain enclosure,

welding said guide members to said longitudinal edges along said weld edges. whereby weld material will not project through to the interior of the chain enclosure. 

1. The improvement in chain guide apparatus for enclosing a driving chain carrying a driving member in a high temperature environment comprising, a relatively nonporous, homogeneous elongated base plate, said base plate having a lateral dimension greater than the width of the driving chain, a relatively nonporous, homogeneous first guide member having a longitudinal dimension corresponding to said base plate longitudinal dimension and being welded to one of said base plate longitudinal edges, said first guide member having a first guide wall upstanding from said base plate a distance corresponding to the driving chain height, a first guide flange being formed integrally with said first guide wall and having a longitudinal dimension corresponding to said first guide wall longitudinal dimension and being substantially orthogonal to said first guide wall to overlie said base plate, a relatively nonporous, homogeneous second guide member having a longitudinal dimension corresponding to said base plate longitudinal dimension and being welded to the other of said base plate longitudinal edges, said second guide member having a second guide wall upstanding from said base plate a distance corresponding to the driving chain height, a second guide flange being formed integrally with said second guide wall and having a longitudinal dimension corresponding to said second guide wall longitudinal dimension and being substantially orthogonal to said second guide wall to overlie said base plate, thereby forming a chain enclosure, the longitudinal edges of said first and second flanges being spaced apart a predetermined distance to form a longitudinal guide slot adapted to receive and guide said chain driving member.
 2. An apparatus in accordance with claim 1 with said base plate and guide members being formed of stainless steel.
 3. An apparatus in accordance with claim 1 with said first and second guide members overlapping the longitudinal edges of said base plate to provide a weld edge externally of the chain enclosure, said flanges being welded along said external weld edge thereby minimizing weld material interiorly of the chain enclosure.
 4. A method of fabricating a chain guide for use in a high temperature environment comprising the steps of, forming a base plate of elongated rectangular shape of relatively nonporous, homogeneous material, forming a pair of elongated guide members of relatively nonporous, homogeneous material, having a longitudinal dimension corresponding to the base plate longitudinal dimension, bending each of said guide members along a longitudinal line to form a longitudinal, integral right angle flange on each of said guide members, welding one of said guide members to one of the longitudinal edges of said base plate and welding the other of said guide members to the other of the longitudinal edges of said base plate so that said guide members extend towards one another to form a chain enclosure and said flanges are spaced apart one from the other to define a longitudinal guide slot.
 5. The method of claim 4 with the step of welding the guide members to the longitudinal edges comprising, overlapping the guide members with the longitudinal edges of the base plate to form weld edges exteRnally of the chain enclosure, welding said guide members to said longitudinal edges along said weld edges whereby weld material will not project through to the interior of the chain enclosure. 